title: Bimanual microincision phacoemulsification in treating hard  cataracts using different power modes.
abstract: OBJECTIVE
  To compare the performance of the Multiburst mode, the Shortpulse mode and the Whitestar technology of the Sovereign platform in treating hard cataracts with bimanual microincision phacoemulsification.
  
  
  METHODS
  101 eyes with hard cataracts (nuclear density Grade 3 and Grade 4 or above) were randomized into three groups. Bimanual microincision phacoemulsification was performed using the Multiburst mode, the Shortpulse mode and the Whitestar technology of the Sovereign phacoemulsification machine respectively. The average power, total duration of ultrasonic power release (US Time), effective phaco time, complications, best-corrected visual acuity and rate of corneal endothelial cell loss were measured and compared among the study groups.
  
  
  RESULTS
  For hard cataracts of various nuclear densities, average ultrasonic power was highest in the Whitestar group followed by the Shortpulse group. The Multiburst group had the highest US Time, effective phaco time and rate of corneal endothelial cell loss whereas the Whitestar Group had the lowest.The differences between the groups were found to be statistically significant by variation analysis and the Fisher's least significant difference procedure. However, there were no significant differences between the USTime values of the Shortpulse Group and the Whitestar Group (P = 0.051). In the Multiburst Group, wound burn occurred in one eye, and three eyes had abnormal fluctuations in the anterior chamber depth.
  
  
  CONCLUSIONS
  The Whitestar technology showed the best performance in this study.The Multiburst mode was proved to be a relatively unsuitable ultrasonic power mode in treating hard cataracts with bimanual microincision phacoemulsification.
authors.affiliation: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China. liuyizhi62@163.com
authors.forename: Yizhi
authors.initials: Y
authors.lastname: Liu
authors.forename: Yuzhen
authors.initials: Y
authors.lastname: Jiang
authors.forename: Mingxing
authors.initials: M
authors.lastname: Wu
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Liu
authors.forename: Tieying
authors.initials: T
authors.lastname: Zhang
mesh_terms: D000368:Aged; D002386:Cataract / Q000473:pathology* / Q000503:physiopathology; D002452:Cell Count; D004728:Endothelium, Corneal / Q000473:pathology; D006801:Humans; D008866:Microsurgery; D008875:Middle Aged; D018918:Phacoemulsification / Q000009:adverse effects / Q000379:methods* / Q000592:standards; D011184:Postoperative Period; D013997:Time Factors; D014465:Ultrasonics; D014792:Visual Acuity